Nucleated Cell Recovery Research Articles

Umbilical Cord Blood Processing Techniques and Their Comparative Advantages: A Review

Background: Umbilical Cord Blood (UCB) has steadily gained prominence in haematopoietic stem cell transplantation (HSCT). Despite UCB advantages, the main disadvantage of UCB in haematopoietic stem cell transplantation (HSCT) is its limited cell dose. Initially, UCB used to be processed and then made to undergo cryopreservation as whole cord blood banking leading to the problem of storing sufficiently large number of cryoprotected UCB units which requires vast amounts of costly storage space in liquid nitrogen. The sole purpose of processing is to concentrates the stem cells and reduce the volume for storage. Different UCB processing methods have been developed. 
 Aim: This review is aimed at bringing together the literature on the different processing methods and highlighting the underlying principles of each method, the relative efficiency and advantages of the methods.
 Methodology: The work involved mainly the critical review of all available academic, professional and industry documents on cord blood processing. The relevant information was obtained from textbooks, academic journals, conference proceedings, the internet among others. The major UCB processing methods include Plasma Depletion, Density Gradient Centrifugation (DGC), Hetastarch, PrepaCyte-CB and Sepax. A study of the potential impact of Hetastarch and PrepaCyte processing methods on transplantation outcomes revealed no difference that was significant was observed between patients receiving cells after the processing regimens were compared.
 Results: A comparison of the engraftment time of PrepaCyte-CB with five other processing methods revealed a quicker engraftment time for PrepaCyte-CB processed cord blood units compared to other processing methods. PrepaCyte-CB also recovers significantly more viable stem cells than AutoXpress (AXP) and hydroxyethyl starch (HES) processing methods. Other workers demonstrated that Sepax depletion produces higher recovery of cells that are nucleated. The effect initial volume of cord blood had on the recovery of nucleated cells for the different method of processing were also compared. Recovery when using Sepax is reduced as the unit size processed increases. Hetastarch, which is a density gradient, and plasma depletion separation is also affected in like manner, however, processing done using PrepaCyte-CB was not affected by the initial volume of the collected unit. The advantage of Sepax is that it is fully automated and this allows for mass processing of samples, suitable for bigger cord blood banks. For erythrocyte removal, density gradient separation is a better method that is effective. PrepaCyte-CB is the second most efficient method for removing RBC. The result of Total Nucleated Cells (TNC) and Mono Nucleated Cells (MNC) recovery rate of Hespan and Sepax against AXP processing methods shows that both Hespan and Sepax reproducibly recover greater than 95% of the cord blood stem cells in a typical collection and result in a reduced final volume for final storage.
 Conclusion: The five most popular processing techniques are Plasma Depletion, Density Gradient, Hetastarch, PrepaCyte-CB and Automated Centrifugal Machine (Sepax). Most methods involve centrifugation, sedimentation and/or filtration for reducing the red cell content, plasma volume, or both. The different UCB processing methods each has its advantages and disadvantages.

Preparation of cryopreserved chimeric antigen receptor T cells for the locoreogional delivery to the neural axis

Background aimsIntracranial (IC) locoregional delivery of chimeric antigen receptor (CAR) T cells presents an attractive delivery method to central nervous system tumors. Although IC delivery is actively being employed in early-phase clinical studies, no thaw/wash methods have been published to remove the neurotoxic cryoprotectant dimethyl sulfoxide (DMSO) from CAR T-cell products before IC administration. Thus, the aim of this study was to develop and validate a simple thaw/wash procedure. MethodsWe developed a thaw/wash procedure that consist of product thaw at 37°C, equilibration for 5 min in 1 volume of preservative-free normal saline (PFNS), dilution with an additional 8 volumes of PFNS, removal of DMSO through a washing step, resuspension in 2.0 mL of PFNS and storage in a syringe at 20–25°C. Final formulated products (FPs) were assessed for quality and safety attributes and stability over 3 h from the completion of the thaw. Stability parameters included CAR T-cell viability, transgene surface expression and cytolytic activity. ResultsThe developed procedure reduced the calculated % of DMSO to less than 0.025%. FP cell viability and recovery (versus pre-cryopreservation) were within acceptable specifications (mean viability: 85.3%, range: 83%–88%; total nucleated cell recovery mean: 76.5%, range: 65.4%–82.5%). Other prespecified quality assurance/quality control parameters including appearance/ integrity, sterility and endotoxin level (≤1.0 EU/mL), were also met by all FPs (n = 3). Three hours’ post thaw/wash stability was confirmed. All products maintained cell viability greater than 70% (mean, 80.0%; range, 79%–81%), with no significant change in transgene expression or cytolytic activity of B7-H3-CAR T cells compared with thawed not diluted/washed control CAR T cells. ConclusionsWe have developed a simple thaw/wash procedure to prepare B7-H3-CAR T cells for their locoregional delivery to the neural axis. While we focus here on CAR T cells, the methods could be readily adapted to other cryopreserved immune effector cell products.

Single laboratory evaluation of umbilical cord blood units processing methodologies for banking.

To compare the efficiency of 3 different processing methods (Sepax, AutoXpress [AXP], and manual processing with hydroxyethyl starch [HES] sedimentation) used at Stemlab during a 10-year period. Historical data were compiled and the analytical results obtained for the 3 different methods were compared. The manual processing (HES) method yielded the highest level of total nucleated cell recovery after processing, and the AXP system yielded the highest CD34+ cell number. The red blood cell reduction was also significantly higher with the HES method. Also, HES showed comparable results to Toticyte technology for umbilical cord blood (UCB) processing. These results show that the HES method is as effective as automated technologies for UCB volume reduction; hence, it is a suitable methodology for private and public UCB banks. The HES method also proved to be superior to Toticyte technology for medical applications, with higher recovery yields of total nucleated cells after thawing and equivalent CD34+ cell recovery and functionality.

Effects of extended transport on cryopreserved allogeneic hematopoietic progenitor cell (HPC) product quality and optimal methods to assess HPC stability.

Since the beginning of the COVID-19 pandemic, cryopreservation of hematopoietic progenitor cell (HPC) products has been increasingly used to ensure allogeneic donor graft availability prior to recipient conditioning for transplantation. However, in addition to variables such as graft transport duration and storage conditions, the cryopreservation process itself may adversely affect graft quality. Furthermore, the optimal methods to assess graft quality have not yet been determined. A retrospective review was performed on all cryopreserved HPCs processed and thawed at our facility from 2007 to 2020, including both those collected onsite and by the National Marrow Donor Program (NMDP). HPC viability studies were also performed on fresh products, retention vials, and corresponding final thawed products by staining for 7-AAD (flow cytometry), AO/PI (Cellometer), and trypan blue (manual microscopy). Comparisons were made using the Mann-Whitney test. For HPC products collected by apheresis (HPC(A)), pre-cryopreservation and post-thaw viabilities, as well as total nucleated cell recoveries were lower for products collected by the NMDP compared to those collected onsite. However, there were no differences seen in CD34+ cell recoveries. Greater variation in viability testing was observed using image-based assays compared to flow-based assays, and on cryo-thawed versus fresh samples. No significant differences were observed between viability measurements obtained on retention vials versus corresponding final thawed product bags. Our studies suggest extended transport may contribute to lower post-thaw viabilities, but without affecting CD34+ cell recoveries. To assess HPC viability prior to thaw, testing of retention vials offers predictive utility, particularly when automated analyzers are used.

Abstract 23 A First Insight into the Validity of Post-Thaw Cell Recovery, Viability, and Potency Over Time

IntroductionTesting of a thawed segment or representative sample of a cord blood unit (CBU) for cell recovery, viability, and potency forms part of pre-release testing. Not all CBUs that have had pre-release testing completed are shipped for transplant, due to postponed or cancelled shipment request, and are therefore kept in the inventory until they are searched again. In an effort to identify these CBUs for future expedited release, the World Marrow Donor Association (WMDA) initiated a project to flag them as “Ready to Ship” in the WMDA Search & Match Service. However, it is not known how long post-thaw results are valid before they must be repeated on another thaw. Such information can be beneficial not only for transplant centers to better assess CBU suitability but also for Cord Blood Banks (CBBs) to avoid unnecessarily exhausting their precious samples.ObjectiveThis study aimed to provide a first insight into the validity of post-thaw results over various lengths of time.MethodsNineteen CBUs, collected between 2003 and 2015 at the BMDI CBB and that had post-thaw testing performed twice, were analyzed for change in the total nucleated cell (TNC) recovery, total CD34 cell recovery, CD34 cell viability, and CFU-GM counts between two thaws.ResultsThe 19 CBUs were grouped into 4 groups based on their storage time between thaws. An average decrease in TNC recovery of 5.3% from first thaw to second thaw was observed for the entire dataset (P = .015). Four CBUs with a greater than 10% decrease had a bag TNC greater than 25 × 108. Individual CBU data is shown in Figure 1. No significant change between thaws was seen with total CD34 recovery (P = .738) or CD34 viability (n = 9 pairs, P = .354). A large variation in CFU-GM counts was observed between thaws. It is worth noting that all CBUs met CBB release criteria of >60% TNC recovery and that CD34 viabilities were above 70% (FACT requirement) in both thaws.Figure 1.Comparison of first and second thaw TNC recovery (A), total CD34 recovery (B), CD34 viability (C), and CFU-GM counts (D) of individual cord blood unit, grouped into 4 groups based on their storage time between thaws: 0-6 months (i), 2-3.5 years (ii), 6-8.5 years (iii), and 12 years (iv).DiscussionWhile results need to be confirmed on a larger dataset, our preliminary data shows very little change in post-thaw cell recovery and viability over various lengths of time (2 months-12 years), suggesting post-thaw results may be valid for longer than 10 years.

How do I warm HPC(A) products to maximize cell viability in the setting of cold agglutinin disease?

High titers of cold agglutinins jeopardize the quality of an apheresis product meant for autologous or allogeneic transplant. Management of transplant patients with cold agglutinin disease (CAD) is often experience-based and under reported, yet decisions must be made quickly to optimize product management and patient outcomes. There remains a lack of data quantifying cell recovery and viability when using various warming methodologies. To expand the published experimental data on this subject, our human cellular therapy lab compared cellular recoveries and viabilities after manipulation of cryopreserved apheresis products through various warming methodologies: (1) extended warming in a water bath, (2) warming via blood warmer and infusion pump, and (3) warming in a water bath followed by infusion pump as a control to assess potential shear stress effects. The presented studies demonstrate that all methods of product warming produce the same rates of recovery of total and viable cells across vital cell types prior to patient administration. Statistically, use of an extended water bath protocol provided a marginal benefit in recovery of total nucleated cells, though this effect is diminished when products are held for an extended period to simulate a delay in administration. These results can inform decisions to improve patient care and minimize product manipulation and loss. Centers are encouraged to use this information to guide proactive measures to establish a standard operating procedure to manage CAD cases.

Washing transplants with Sepax 2 reduces the incidence of side effects associated with autologous transplantation and increases patients' comfort.

High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (ASCT) is routinely used in various hematologic malignancies. However, dimethylsulfoxide contained in cryopreserved grafts can cause adverse events (AEs). Forty-three ASCTs were performed with Sepax 2 washed grafts between 7/2016 and 10/2019. The aim of this study was to determine whether washing out dimethyl sulfoxide (DMSO) from transplants using the Sepax 2 (S-100) device is safe and reduces the incidence of DMSO-associated AEs. The washing procedure was automated and that resulted in the satisfactory recovery of total nucleated cells, CD34+ cells, and colony forming units of granulocyte and macrophages (85%, 80%, and 84%, medians). Time to engraftment of leukocytes, granulocytes, and platelets as well as the number of neutropenic days did not differ when compared to 20 consecutive ASCTs without washing. The AE occurrence was lower compared to unwashed grafts: 81% versus 78% during and shortly after grafts administration, 76% versus 69% in the following day. We conclude that the washing of cryopreserved transplants using Sepax 2 was feasible with a high recovery of hematopoietic cells, did not influence time to engraftment, and resulted in the satisfactory reduction of AEs and improved tolerance of the procedure.

Analysis of outcomes of single-unit cord blood transplantation with umbilical cord blood units processed with two different red blood cell sedimentation reagents.

Various processing methodologies are routinely used to reduce volume and red blood cell content of umbilical cord blood (UCB) units collected for hematopoietic stem cell transplantation. There is limited information regarding effects of UCB processing techniques on clinical outcomes. Retrospective data analysis compared laboratory and clinical outcomes following single-unit UCB transplantation performed between 1999 and 2015. All UCB units were from St. Louis Cord Blood Bank and all were manually processed with either Hetastarch processed cord blood units (HCB) (n= 661) or PrepaCyte processed cord blood units (PCB) (n= 84). Additional sensitivity analysis focused on units transplanted from 2010 to 2015 and included 105 HCB and 84 PCB. There were no significant differences in patient characteristics between the two groups. Pre-freeze total nucleated and CD34+ cell counts, cell doses/kg of recipient weight, and total colony-forming units (CFUs) were higher in PCB compared with HCB. Post-thaw, the PCB group had a significantly better total nucleated cell recovery, while there were no significant differences in cell viability, CFU recovery, or CD34+ cell recovery. Primary analysis demonstrated faster neutrophil and platelet engraftment for PCB but no differences in overall survival (OS), whereas sensitivity analysis found no effect of processing method on engraftment, but better OS in the HCB group compared with PCB group. The UCB processing method had no significant impact on engraftment. However, we cannot completely exclude the effect of processing method on OS. Additional studies may be warranted to investigate the potential impact of the PCB processing method on clinical outcomes.

Prospects on the Potential In Vitro Regenerative Features of Mechanically Treated-Adipose Tissue for Osteoarthritis Care

Gathering a better grasp on the adipose stromal vascular fraction (SVF) is demanding among clinicians for osteoarthritis (OA) care because of its promising but multifaceted clinical outcomes. The aim of this preclinical in vitro study was to test whether the mechanical approach with Hy-Tissue SVF system, a class IIa CE marked device of adipose tissue micro-fragmentation, influences the biological features and functions of SVF. We compared mechanical generated-SVF (mSVF) with the enzymatic generated-SVF (eSVF) by testing cell survival, phenotype, differentiation, and paracrine properties using ELISA assays. Both adipose SVF showed 80% viable cells and enrichment for CD-44 marker. The mSVF product preserved the functions of cell populations within the adipose tissue; however, it displayed lowered nucleated cell recovery and CFU-F than eSVF. As for multipotency, mSVF and eSVF showed similar differentiation commitment for osteochondral lineages. Both adipose SVF exhibited an increased release of VEGF, HGF, IGF-1 and PDGF-bb, involved in pathways mediating osteochondral repair and cell migration. Both mSVF and eSVF also displayed high release for the anti-inflammatory cytokine IL-10. After in vitro culture, supernatants from both mSVF and eSVF groups showed a low release of cytokines except for IL-10, thereby giving evidence of functional changes after culture expansion. In this study, mSVF showed active cell populations in the adipose tissue comparable to eSVF with excellent survival, differentiation and paracrine properties under a new mechanical adipose tissue micro-fragmentation system; thereby suggesting its potential use as a minimally invasive technique for OA treatment.Graphical abstract

Hydroxyethyl starch is an alternative washing solution for peripheral bloodstem cells products

Cryopreservation of hematopoietic stem cells (HSC) involves slow rate cooling in the presence of a cryoprotectant (DMSO) to avoid the damaging effects of intracellular ice formation. The infusion of DMSO with the thawed product has been related to adverse events. Reduction of DMSO content by washing the HSCs after thawing has been suggested as a method to avoid infusion-related side-effects. Albumin-dextran washing methods have proved useful in thawing HSC products. Dextran40 shortages prompted us to search for suitable alternatives. We report the results of a comparative study of the use of hydroxyethyl starch (HES) as an alternative to dextran40 for washing thawed HSCs products. A total of 10 HSC bags cryopreserved with 10 % DMSO were used. We conducted a paired study; one of the bags was thawed and washed with our standard washing solution (Dextran 40) and the paired bag with HES solution with a final HES and Human Serum Albumin (HSA) concentration of 2.4 % and 4.2 % respectively. Each final product was tested immediately after washing (sample 0’) and after 90 min (sample 90’) for total nucleated cells (TNC) recovery, acridine orange viability, viable CD34+ enumeration, and clonogenicity. No significant difference was found for any of the cell counts, viability tests, cell recovery, or potency. We can state that the washing solution based on 2.4 % HES and 4.2 % HSA is equivalent to that used in our routine practice. Therefore, we could use the solution with HES, paying special attention to the renal function of the recipient.

Transient warming affects potency of cryopreserved cord blood units

Background aims. Cryopreserved cord blood units (CBUs) can be exposed to transient warming events (TWEs) during routine banking operations, which may affect their potency. NetCord-FACT guidelines recommend removal of these CBUs from inventory. The objective of this work was to evaluate warming kinetics of frozen CBUs in different settings to determine the optimal working environment and define the impact of different TWE scenarios on CB post-thaw quality and potency. MethodsThe warming kinetics of frozen CBUs was influenced by both working surfaces and ambient working temperature, with cold plates providing better protection than vinyl or metal surfaces. Measurement of time for required operational activities revealed that CBUs are probably exposed to core temperatures greater than –150°C even when cold plates are used to reduce warming rates. ResultsOn the basis of the warming kinetics and observed operational activities, three TWE causing scenarios (control, typical, worst case) were investigated using a pool-and-split design and cell viability, recovery and potency (colony-forming unit [CFU]) assays were performed. TWEs were found to have little impact on the recovery of total nucleated cells or on the viability of CD34+ cells. In contrast, the viability and recovery of CD45+ cells in the smaller CBU compartments were reduced by TWEs. Moreover, the worst-case TWE reduced CFU recovery from CBUs, whereas the typical-scenario TWE had little effect. Conclusions. Our results demonstrate that the distal segment underestimates the viability and potency of CBUs and that TWEs can affect the post-thaw viability and potency of CBUs. Although TWEs are almost inevitable during cord-blood banking operations, their effects must be diminished by reducing exposure time, using cold plates and strict operational protocols, to prevent worst-case TWEs.

A modified CD34+ hematopoietic stem and progenitor cell isolation strategy from cryopreserved human umbilical cord blood.

Umbilical cord blood (UCB) is a source of hematopoietic stem cells for transplantation, offering an alternative for patients unable to find a matched adult donor. UCB is also a versatile source of hematopoietic stem and progenitor cells (hCD34 + HSPCs) for research into hematologic diseases, in vitro expansion, ex vivo gene therapy, and adoptive immunotherapy. For these studies, there is a need to isolate hCD34 + HSPCs from cryopreserved units, and protocols developed for isolation from fresh cord blood are unsuitable. This study describes a modified method for isolating hCD34 + HSPCs from cryopreserved UCB. It uses the Plasmatherm system for thawing, followed by CD34 microbead magnetic-activated cell sorting isolation with a cell separation kit (Whole Blood Columns, Miltenyi Biotec). hCD34 + HSPC phenotypes and functionality were assessed in vitro and hematologic reconstitution determined in vivo in immunodeficient mice. Total nucleated cell recovery after thawing and washing was 44.7 ± 11.7%. Recovery of hCD34 + HSPCs after application of thawed cells to Whole Blood Columns was 77.5 ± 22.6%. When assessed in two independent laboratories, the hCD34+ cell purities were 71.7 ± 10.7% and 87.8 ± 2.4%. Transplantation of the enriched hCD34 + HSPCs into NSG mice revealed the presence of repopulating hematopoietic stem cells (estimated frequency of 0.07%) and multilineage engraftment. This provides a simplified protocol for isolating high-purity human CD34 + HSPCs from banked UCB adaptable to current Good Manufacturing Practice. This protocol reduces the number of steps and associated risks and thus total production costs. Importantly, the isolated CD34 + HSPCs possess in vivo repopulating activity in immunodeficient mice, making them a suitable starting population for ex vivo culture and gene editing.

Monitoring of Stored Hematopoietic Stem/Progenitor Graft Stability Program in a Single Institute

Cryopreservation of hematopoietic stem/progenitor cell (HPC) grafts and other cell based products to be infused in the future is a common practice. However, cryopreservation and conditions of storage can influence post thaw recovery of cellular products. HPC graft is composed of heterogeneous blood cells. Various assays detect viability based on different principles and their sensitivity differs. Less than 1 in 100,000 CD34+ cells possess in vivo hematopoietic reconstitution potential, therefore determination of viability and recovery need to be interpreted accordingly. We analyzed total 38 graft aliquots stored in liquid nitrogen (auto 10 yrs = 7, Auto 1 yr = 12, allo 10 yrs = 5, Allo 5 yrs = 5, allo 1 yr = 9). The viable CD34+ cell frequency in allo HPC grafts was higher than auto grafts cryopreserved 10 years ago (Auto 10 yrs = 0.39 ± 0.24%, Allo 10 yrs = 0.96 ±0.31%, Allo 5 yrs = 0.82 ± 0.3%, p = 0.018). When we compared both single and dual ISHAGE platform methods it displayed comparable post thaw viable CD34+ cell numbers (Figure 1A). The recovery of viable total nucleated cells (TNC) based on trypan blue dye exclusion was 46.83± 4.98% auto 10 years, 43.11 ± 7.76% allo 10 years, 48.74 ± 4.94% allo 5 years, 87.56 ± 6.93% allo 1 year. The viable CD34+ cell recovery between the groups were comparable (Figure 1B). Auto HPC grafts stored for more than 10 years displayed 64.05±16% while auto grafts stored less than a year yielded 85.4±15.15% viable CD34 recovery. The effects of storage duration on grafts is presented below by monitoring hematopoietic engraftment after transplantation. Interestingly, auto grafts in comparison to allo grafts stored for 5 to10 years displayed higher red fraction (JC-1); indicative of higher mitochondrial membrane potential (MMP) and viability (Auto 10 yrs = 72.24 ± 12.45%, Allo 10 yrs = 40.6 ± 13.92%, Allo 5 ysr = 47.2 ± 15.36%, p = 0.011). The higher fraction of cells with intact MMP (red fraction) within CD34+ cell compartment of post thaw suggesting likely higher resilience of auto grafts. Samples stored up to10 years displayed positive colony forming unit (CFU) growth but had poor CFU recovery. CFU recovery for HPC grafts stored for less than 1 year displayed 82.93 ± 25.68% for auto grafts while allo graft displayed 72.46 ± 34.76%. HPC grafts stored for 5 to 10 years which were utilized here to determine graft stability were transplanted within two months of storage and displayed timely neutrophil and platelet engraftment. When single ISHAGE platform method was used to enumerate viable CD34+ cells and HPC grafts are thawed within one year, viable CD34 recovery for auto HPC graft was 85.4 ± 15.15% and for allo graft recovery was 86.85 ±18.0%. Four patients which were transplanted (CD34+ cells infused mean ± SD, 4.35 ± 1.43 x 10e6/KG body weight) with autologous grafts stored for 5 to 8 years in liquid nitrogen (vapor phase) displayed timely neutrophil (9.5 ± 1 day) and platelet (16.5 ± 5 day) engraftment. Taken together, viability assays detect various aspects of cell integrity. The post thaw viable CD34 recovery corresponds well with in vivo hematopoietic reconstitution but in some instances functional potency assays particularly for samples stored longer than 5 years may be crucial. The relatively higher resilience of auto HPC grafts stored for longer than10 years is of note which will need to be further validated. Disclosures Patel: Celgene: Speakers Bureau; Janssen: Speakers Bureau; Amgen: Consultancy, Speakers Bureau.

Effect of Long-Term Storage on Hematopoietic Progenitor Cell Transplant Product Quality

Abstract Hematopoietic progenitor cell (HPC) transplant product quality indicators after prolonged cryopreservation are variable. A recent study in Europe demonstrated wide variability of cryopreservation times, from 1 to >20 years, with most centers storing products for 5 or 10 years. Thawed HPC viability using various ex vivo means and in vivo by studying neutrophil and platelet engraftment has generally supported preservation of CD34+ viability with prolonged storage. However, sample size, methods, and timepoints varied, and clear guidelines currently do not exist regarding how long HPCs can be stored. This study’s objectives include an evaluation of HPC quality indicators over time and if HPC product age and/or viability correlates with HPC engraftment. Retrospective record review was conducted on 837 HPC products thawed between January 1, 2011, and December 31, 2018. HPC products were sampled and characterized at thawing by flow cytometry for total nucleated cell (TNC) recovery, CD34+ recovery, and CD34+ viability (by 7-AAD). Preestablished acceptability criteria for TNC recovery, CD34+ recovery, and CD34+ viability were >80%, >40%, and >60%, respectively. If available, products with ANC engraftment data were further analyzed to correlate data with time to HPC engraftment. HPC products were stored between 3 and 5,943 days; 816 products were infused, ranging from 3 to 5,273 days in storage. Most (81%) HPC transplants occurred within the first year, 47 infusions occurred after storage >5 years, and 4 infusions occurred after storage >10 years. CD34 viability and percent recovery of TNC and CD34 were not significantly different as time in storage increased. Given sample paucity, 19 samples stored for >10 years were analyzed in individual years and grouped. In total, 96.5% samples stored for <1 year and 68% in samples stored >10 years met acceptability criteria for >60% CD34+ recovery; 98.9% samples stored <1 year met the >60% CD34+ viability acceptability threshold versus 90% of samples stored for >10 years. The oldest sample infused after storage of 5,273 days (14.4 years) showed 42% TNC recovery, 19% CD34+ recovery, and 84% CD34 viability; ANC engraftment data were not available. Sixty-five samples containing ANC engraftment data showed that time to ANC engraftment ranged from 9 to 15 days. No clear trend was present for viability or CD34 recovery when compared with days to engraftment based on limited data. Although rare, infusion of HPC products of extended duration occurs. This study suggests that HPC product quality may decrease after extended cryopreservation based on preestablished acceptability criteria. The oldest sample infused had preserved CD34+ viability despite significantly less TNC and CD34+ recovery, suggesting thawing might select for more robust HPCs. More studies with older samples are needed to determine the clinical impact of cryopreservation and if modification of current quality indicators could be useful clinically.

ABO-mismatched marrow processing for transplantation: Comparative results of 80 procedures performed with Cobe Spectra and Spectra Optia

Backgroundremoval of incompatible red blood cells (RBCs) or plasma is usually required to avoid hemolysis during infusion of ABO incompatible bone marrow (BM) allogeneic transplants. This process often involves separation of buffy coat (BC) by centrifugation in automated devices. We have evaluated the Spectra Optia™ (Optia) apheresis system to determine its effectiveness in BC concentration, volume reduction and RBCs depletion of ABO-incompatible BM compared with our previous method using Cobe Spectra™ (Cobe). Materials and methods28 processes were performed with Optia and 52 with Cobe. We compared volume reduction, RBCs depletion, and recovery of total nucleated cells (TNCs), mononuclear cells (MNCs), CD34+ and CD3+ cells in the final product. Hematopoietic engraftment was ascertained. We used Saphiro-Wilks and Kolmorgorov- Smirnov tests to test normality and Mann-Whitney’s U test to compare means between both groups. ResultsWe found statistically significant differences favoring Optia versus Cobe in TNCs recovery (62% vs. 37%), CD34+ cell recovery (98 vs 84%), volume reduction (91 vs 84%), and RBCs depletion (99 vs. 97%), but not in processing time or time to engraftment. ConclusionOptia achieves high RBCs and volume depletion of BM, while providing excellent CD34+ recovery in clinical routine. Some parameters compare favorably with Cobe Spectra.

Validating and implementing the use of an infusion pump for the administration of thawed hematopoietic progenitor cells-a single-institution experience.

Direct thaw and administration of previously cryopreserved peripheral blood stem cell products is a commonly used practice and should be performed rapidly to reduce cellular damage caused by dimethyl sulfoxide exposure. Cells are typically thawed at the bedside and infused by gravity through a high-flow-rate central venous catheter. An existing nontunneled catheter is occasionally used instead and often results in a slower infusion rate. To ensure expedient and consistent infusions, we validated and implemented the use of an infusion pump for thawed peripheral blood stem cells. Validation was performed in two phases: in vitro simulation and in vivo clinical assessment. Total nucleated cell recovery and viability plus progenitor cell viability and potency were compared in vitro between two cryopreserved peripheral blood stem cell units that were either passed through a preset infusion pump or drained by gravity. The infusion rate, adverse events, and engraftment times were retrospectively compared between patients who received infusions by infusion pump (n = 35) and by gravity (n = 38). No significant differences were observed in vitro between the infusion methods for all measured variables. Overall infusion rates were similar in vivo for both groups but were significantly lower for patients who had nontunneled catheters that delivered the infusion by gravity. The time to neutrophil and platelet engraftment was similar for both groups. This is the first study to assess the use of an infusion pump for stem cell transplant. The use of an infusion pump for peripheral blood stem cell infusion is safe, provides a reliable and consistent infusion method, and can mitigate the effect of the type of venous access line used.

RareCyte® CTC Analysis Step 1: AccuCyte® Sample Preparation for the Comprehensive Recovery of Nucleated Cells from Whole Blood.

The RareCyte platform addresses important technology limitations of current circulating tumor cell (CTC) collection methods, and expands CTC interrogation to include advanced phenotypic characterization and single-cell molecular analysis. In this respect, it represents the "next generation" of cell-based liquid biopsy technologies. In order to identify and analyze CTCs, RareCyte has developed an integrated sample preparation, imaging and individual cell retrieval process. The first step in the process, AccuCyte®, allows the separation, collection, and transfer to a slide the nucleated cell fraction of the blood that contains CTCs. Separation and collection are based on cell density-rather than size or surface molecular expression-and are performed within a closed system, without wash or lysis steps, enabling high CTC recovery. Here, we describe our technique for nucleated cell collection from a blood sample, and the spreading of these nucleated cells onto glass slides permitting immunofluorescent staining, cell identification, and individual cell picking described in subsequent chapters. In addition to collection of rare cells such as CTCs, AccuCyte also collects cells of the circulating immune system onto archivable slides as well as plasma from the same sample.

Comparison of two methodologies for the enrichment of mononuclear cells from thawed cord blood products: The automated Sepax system versus the manual Ficoll method

Background aimsUmbilical cord blood (CB) is being used as a source of hematopoietic stem cells (HSCs) and immune cells to treat many disorders. Because these cells are present in low numbers in CB, investigators have developed strategies to expand HSCs and other immune cells such as natural killer (NK) cells. The initial step in this process is to enrich mononuclear cells (MNCs) while depleting unwanted cells. The manual method of MNC enrichment is routinely used by many centers; however, it is an open system, time-consuming and operator dependent. For clinical manufacturing, it is important to have a closed system to avoid microbial contamination. MethodsIn this study, we optimized an automated, closed system (Sepax) for enriching MNCs from cryopreserved CB units. ResultsUsing Sepax, we observed higher recovery of total nucleated cells (TNC), CD34+ cells, NK cells and monocytes when compared to manual enrichment, despite similar TNC and CD34+ viability with the two methods. Even though the depletion of red blood cells, granulocytes and platelets was superior using the manual method, significantly higher CFU-GM were obtained in MNCs enriched using Sepax compared to the manual method. This is likely related to the fact that the automated Sepax significantly shortened the processing time (Sepax: 74 – 175 minutes versus manual method: 180 – 290 minutes). The use of DNAse and MgCl2 during the Sepax thaw and wash procedure prevents clumping of cells and loss of viability, resulting in improved post-thaw cell recovery. DiscussionWe optimized enrichment of MNCs from cryopreserved CB products in a closed system using the Sepax which is a walk away and automated processing system.

Abstract 369: Automating recovery of spiked tumor cells from blood

Abstract The isolation and study of circulating tumor cells (CTC) enables personalized medicine solutions, monitoring of therapeutics (theragnostics), and monitoring of minimal residual disease (MRD); culturing these rare cells is a frequent goal in cancer research, however the common methods for their isolation (gradient centrifugation, lysis buffer) are damaging to these cells, and many emerging technologies leave the cells bound in a consumable, bound to a biomarker or in a state that is difficult to use in cell culture. Further, the anuclear cells in blood greatly outnumber nucleated cells and present significant challenges to the study of the nucleated cells, for example, erythrocytes can absorb excitation or emission wavelengths in fluorescence studies, and their shape promotes rouleaux formation which can sequester the cells of interest; platelets also have a tendency to be activated by physical handling and cause aggregation that can also sequester and damage the cells of interest, and these all contain the greatest content of RNA and other markers that increase background noise in many assays. We demonstrate a new technology that automates the depletion of erythrocytes, thrombocytes, and plasma markers from, initially, small volumes of blood, using a micromachined membrane filter. We spiked small counts (10 to 1000 estimated from dilution) of tumor cell lines BT474 (breast cancer), DLD1 (colorectal cancer), and K562 (myelogenous leukemia) and other cell types into aliquots of blood. Using calcein-AM-loading to distinguish the spiked cells from blood cells, the recovery rates were determined in a flow cytometer, indicating an average of 80% ±4% (SE, N = 27) recovery of the rare cells after depletion of anuclear cells and plasma. The technology is amenable to use of beads for initial negative depletion of common nucleated cells by magnetic beads and has a recovery capacity of a few to as much as 3 million cells per specimen. Tumor cell lines alone that were run through this automation process then seeded for cell culture demonstrated growth rates indistinguishable from those seeded in similar counts in a regular cell passage. In further studies we demonstrate depletion of leukocytes with magnetic beads and of anuclear cells by filtration to handle larger blood volumes. The filtration system may be used for automated recovery of nucleated cells or cell clusters from blood or other fluid samples (liquid biopsies) without use of harsh chemicals or centrifugation, removing a common barrier for emerging analytical approaches. Citation Format: Mark Sarinana, Ky Truong, Keith Cannon, Antonio Guia. Automating recovery of spiked tumor cells from blood. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 369.

72 - Substantially Reduced Red Cell Contamination with Comparative Nucleated Cell Recovery Using Sample Specific Red Cell & Plasma Reduction Techniques (a Retrospective Analysis of 36489 Umbilical Cord Blood Units at Lifecell International Pvt. Ltd.)

72 - Substantially Reduced Red Cell Contamination with Comparative Nucleated Cell Recovery Using Sample Specific Red Cell & Plasma Reduction Techniques (a Retrospective Analysis of 36489 Umbilical Cord Blood Units at Lifecell International Pvt. Ltd.)